Conventional resistor ladder networks (see FIG. 1) are used in automotive vehicle electrical systems due to their ability to provide flexible implementation at low costs. These resistor ladder networks 100 are typically constructed as a voltage divider circuit 102 including a plurality of resistors 104a-104e with different resistive values, and a plurality of switches 106a-106d. Closing any one of the switches 106a-106d alters either the high resistance or the low resistance of the voltage divider circuit 102. The voltage divider circuit 102 comprises a high resistance between a supply voltage 108 and a first terminal 110, and a low resistance between a second terminal 112 and a low voltage reference 114. In this way, the resistance of the network 100 can vary and will exhibit a unique resistance range depending upon the selected state of a particular switch 106a-106d. The range of different resistances, however, cannot be achieved by operating only a single individual switch. Therefore, these conventional resistor ladder networks 100 inherently establish a priority scheme such that an output voltage of the voltage divider 102 indicates whether the switches 106a-106d are closed (e.g., a user switch selection).
However, the priority scheme resulting from conventional resistor ladder networks prevents the vehicle electrical system from simultaneously detecting activated switches. That is, conventional resistor ladder networks are incapable of detecting a state of a first switch independently from the state of the remaining switches included in the resistor ladder network. Therefore, vehicle states are assigned specific priorities which are then assigned to a particular switch based on the switches installed location in the resistor ladder network.